The present invention relates to devices for injecting, infusing, delivering, administering or dispensing substances, and to methods of making and using such devices. More particularly, it relates to an insertion device for an insertion head, an arrangement comprising the insertion device and an insertion head that is or can be received in the device, a use of the insertion device or of the arrangement, and a method for applying or using an insertion head.
In patients with a regular requirement for a medicament that can be administered by direct delivery into the body tissue or into the blood stream, for example certain groups of patients suffering from pain, or patients with type I and type II diabetes, it can be useful to supply the body with the required quantity of medicament in liquid form via a cannula that is introduced at a suitable location into the body and that remains there over quite a long period of time. For this purpose, a cannula arrangement, designated as an infusion set or port, depending on its design, is secured on the patient's skin, such that the cannula passes through the skin and into the body.
Efforts are also increasingly being made to monitor certain medical parameters of a patient, for example the blood sugar value, continuously over quite a long period of time. For this purpose, a sensor arrangement, for example, is placed on the patient's body and, with a puncturing tip of a suitable sensor, passes through the skin and into the patient's body.
To avoid infections, the infusion set, the port or the sensor arrangement has to be changed at regular intervals, for example every three days. In outpatient treatment, for example in the case of diabetics, this is often done by the patients themselves and, on account of the introduction of the infusion cannula or of the puncturing tip into the skin, is associated with a certain amount of pain. It is therefore important that such infusion sets, ports or sensor arrangements can be applied easily and safely, which is why many manufacturers have started designing their products as insertion heads for special insertion devices with the aid of which the insertion heads can be applied to the patient's body. Application is made easier in this way, and the pain occasioned by the application is reduced to a minimum, thanks to the quick and targeted puncturing procedure.
Thus, for example, U.S. Pat. No. 6,607,509 B2 discloses insertion devices for infusion sets, in which the infusion set is placed abruptly onto the application site by the force of a pretensioned spring, and the cannula penetrates into the tissue of the patient. After application of the infusion set, the insertion device has to be uncoupled and removed from the infusion set, which has the disadvantage that this may cause irritation at the puncture site by force exerted on the inserted cannula.
WO 2004/110527 A1 discloses, in addition to insertion devices as described above, also a similar insertion device for infusion sets in which, however, the infusion set is already automatically separated from the insertion device at the start of the insertion movement and then penetrates in free flight into the body of the patient. Compared to the previously described insertion devices, this arrangement affords the advantage that, during the actual puncturing movement, practically no friction losses occur within the insertion device, such that the application can take place at great speed and with a correspondingly short pain interval. Irritation at the puncture site, caused by subsequent detachment of the insertion device from the insertion head, is also avoided. However, said insertion device has the disadvantage of being relatively complicated to use and of requiring a large number of operating steps.